Method of sealing seal end carton



April 1 6, 1968 FRANZ 3,377,767

METHODOFI SEALING SEAL END CARTON Filed March 27, 1964 4 Sheets-Sheet 1 INVENTOR Norman J. Franz ATTORNEY April 16, 1968 N. J. FRANZ 3,377,757

METHOD OF SEALING SEAL END CARTON Filed March 27, 1964 v 4 Sheets-Sheet :2

/, INVENTOR. Norman J. Flronz Fig. 4 imam/Q4 ATTORNEY April 16, 1968 N. .J. FRANZ 3,377,767

V METHOD OF SEALING SEAL END CARTON Filed March 27, 1964 4 Sheets-Sheet f5 Fig. 9

INVENTOR. Norman J. Franz BYJW M ATTORNEY April 16, 1968 N. J. FRANZ 3,377,767

METHOD OF SEALING SEAL END CARTON I Filed March 27, 1964 4 Sheets-Sheet 4 F1 g. 7 INVENTOR.

Norman J. FIIOHZ BY %MM A h ATTORNEY United States Patent 3,377,767 METHDI) 0F SEALING SEAL END CARTON Norman J. Franz, Colerain Township, Hamilton County, Ohio, assignor to The Procter & Gamble Company, Cincinnati, Ohio, a corporation of Ohio Filed Mar. 27, 1964, Ser. No. 355,156 4 Claims. (CI. 53-29) This invention relates to an improved carton and more particularly, to a seal end carton which can be used to package granular or powdery products and the like and a method for sealing the carton.

A commonly used carton for packing powdery products is composed of front, back and side wall panels, all of which have sealing flaps extending therefrom. The length of the sealing flaps extending from the side wall panels is usually less than half the front wall width dimension so that they only partially cover the open end of the carton when both are infolded. On the other hand, the sealing flaps extending from the front and back Wall panels are usually full size, i.e., of a size to extend completely across and cover the end of the erected carton when folded into position. A reduction in the amount of paperboard needed for a carton having a given volume can be obtained by simply reducing the dimensions of these sealing flaps. However, when paperboard is saved in this way, it can cause problems in sealing the ends securely. It also may result in problems of sifting and leakage which occur frequently at the end structure of a carton having relatively small sealing flaps. The problem is particularly troublesome as the carton is being filled and handled on modern high speed packing equipment.

It is an object of this invention to provide an improved carton which will retain granular or powdery products Without leakage during initial packing and under normal conditions of handling and storage.

It is another object of this invention to provide an improved carton in which a minimum of cartonboard material is used and which is especially adapted for use with granular or powdery products.

It is another object to provide a seal end carton in which the end flaps extending from the side walls function as bafiies to serve as a means for preventing material leakage before the final end seal is completed.

Still another object is the provision of an improved carton which can be formed and filled with granular or powdery products on continuous motion, high speed packing equipment without material leakage at the ends of the carton.

These and other objects of the invention which will be set forth hereinafter will become apparent to one skilled in the art upon reading these specifications when taken with the accompanying drawings of the exemplary embodiment.

Briefly summarized, the invention in one embodiment provides a carton having front, rear and side walls with each wall having flaps extending from both ends. The closure flaps attached to the front and rear walls are narrower than the full Width of the side Wall but yet are sufiiciently wide to partially overlap when folded into sealing relationship. Opposed baffle flaps extend from each end of each side wall. The baflle flaps have a special configuration as more fully described hereinafter. The baffle flaps are infolded under the front and rear closure flaps but are not sealed thereto. The bafile flaps in combination with the closure flaps provide a mechanical closure of the carton end prior to final end sealing.

The method of forming the carton comprises the steps of opening and squaring-up the collapsed carton blank, moving the open ended carton over the fixed end of a "ice mandrel, infolding the bafiie flaps against the mandrel and thereafter folding the closure flaps over the mandrel so that the mandrel lies between the baffie flaps and the closure flaps. Before the closure flaps are overlapped, a quick-setting adhesive is applied to the sealing surfaces of the closure flaps. At the free end of the mandrel, the overlapped surfaces of the closure flaps pass between the mandrel and a stationary roller to which an electromagnet is aflixed. The force created by the electromagnetic field draws the mandrel and roller together thereby tightly squeezing together the overlapped surfaces of the closure flaps and the interposed adhesive. After the carton is filled with product, the other end is closed and sealed by a similar method as described above. The carton is completed by adhering the ear-like extensions projecting from the closure flaps to the side walls until the adhesive sets.

While the specification concludes with claims particu larly pointing out and distinctly claiming the subject matter regarded as forming the present invention, it is believed the invention will be better understood from the following description when taken with the accompanying drawings in which:

FIGURE 1 is a plan view of a cut and scored carton blank from which the structure of this invention is made;

FIGURE 2 is a fragmentary view of the carton blank of FIGURE 1 showing a baffle flap in detail;

FIGURE 3 is an isometric view of the squared-up carton with baffle and closure flaps at one end in partially sealed condition;

FIGURE 4 is a sectional view taken on the line 4--4 of FIGURE 3;

FIGURE 5 is a fragmentary sectional view taken on line 5'5 of FIGURE 3;

FIGURE 6 is a fragmentary isometric view showing the infolded baffle flap and closure flaps at an end of the carton; the front panel being removed to permit clear view of the interior;

FIGURE 7 is a fragmentary isometric view showing the carton sealed at one end;

FIGURE 8 is a fragmentary elevation showing the fixed mandrel, stationary roller and electromagnet which can be used to practice the method of the invention;

FIGURE 9 is an expanded fragmentary sectional view taken on lines 99 of FIGURE 8;

FIGURE 10 is a. fragmentary elevation of another fixed mandrel, stationary roller and electromagnet used to close the carton tops in practicing the method;

FIGURE 11 is a sectional view taken on line 11-11 of FIGURE 10;

FIGURE 12 is a top view of the carton showing final sealing of the ears; and

FIGURE 13 is a sectional view taken on line 1313 of FIGURE 12.

FIGURE 1 illustrates the carton blank wherein the dash-dot lines represent conventional score lines and the solid lines represent either the carton outline or cuts in the carton blank. The body of the carton comprises a front wall 21, a side wall 22, a back wall 23, a side Wall 24, and a glue flap separated by score lines as illustrated. Closure flaps 26 and 2S defined by the score lines 27 and 29, respectively, extend from the ends of the front Wall 21. Closure flaps 26 and 28 have ear-like extensions 30, 31 and 32, 33, respectively. In similar fashion, the closure flaps 34 and 36 separated by score lines and 37, respectively, extend from the ends of the back wall 23. Closure flap 34 has ear-like extensions 38 and 39 and closure flap 36 has ear-like extensions 40 and 41. Ears 3t), 31, 32, 33, 38, 39, 40 and 41 are articulated by score lines to the respective closure flaps. As shown, the closure flaps are of generally rectangular configuration. The Width u of each closure flap is greater than one-half the width of the side wall but less than the full width of the side walls. Closure flaps 34 and 36 have adhesive pattern areas 42 and 43, respectively; these areas define the overlapped surface areas of the cooperating closure flaps at each end of the closed carton. The bafile flaps 44 and 46 extend from the sidewall 22. Bafile flaps 44 and 46 are generally arcuate in form and are defined by the score lines 45 and 47, respectively. Side wall 24 is similarly provided with projecting baffie flaps 48 and 50, also of generally arcuate form, separated from the side wall 24 by the score lines 49 and 51, respectively. The closure flaps 26 and 28 are notched as at 52 and 53, respectively.

In FIGURE 2, the form of the bafi le flap 44 is shown in enlarged detail. It will be understood that the other baffle flaps 46, 48 and 50 are of like configuration. As shown, the form of the baffle flap 44 is outlined by the configuration of the cuts a and c, the free edge b and the score line 45 separating the baffle flaps 44 from the side wall 22. The outer edge of the flap 44 intercepts the score line 45 at the points e and f. The cuts a and c are substantially straight lines which sever the bafiie flap 44 from the ears 31 and 38, respectively. The arc-like edge b appears (see FIG. 2) to join cuts a and c tangentially. However, in the preferred embodiment, tangential intersection is not essential. The straight cuts a and c preferably subtend an angle with the score line 45 between about 40 and 50 (the angle p in FIGURE 2). In the preferred embodiment arc b is a portion of a circle on a chord subtended by a central angle of from about 55 to about 90. The arc b has a radius r equal to about one-half of the width of the side wall panel 22. The subtended central angle qs, the corresponding length of arc b, and the length of the straight cuts a and will be varied according to the size and dimensions of the carton as well as the corresponding dimensions of the ears. The above described configuration of the leading edge of the baflie fiap 44 is preferred over a full circular arc or other similar curve because of the need for tight line contact between the edge of the baffle flaps and the surfaces of the closure flaps when the carton is initially closed.

The carton blank of FIGURE 1 may be folded and tubed by ordinary carton making machinery well known to those skilled in the art so that glue flap is securely adhered to the inside surface of front wall 21. Glue flap 25 could extend, alternatively, from front wall 21 and thus be secured to the sidewall 24 when the carton blank is tubed.

In FIGURE 3, the squared up carton of the exemplary embodiment is shown with the top end open and the bottom end partially sealed. For purposes of this invention, however, the order in which the ends are sealed is immaterial. It will be especially noted in FIGURES 3 and 4 that closure flaps 28 and 36 have been folded over bafiie flap 46 to overlap one another. The baffle flap 50 is in a position similar to the baffle flap 46. The closure flaps are adhesively secured at the overlapped portion. At this stage, folding, gluing and sealing of the ears 32, 41 and 33, to the side walls 24 and 22, respectively, remains to be done inv order to complete the end seal. At this stage, the bottom end, as shown in FIGURES 3 and 4 are called partially sealed as distinguished from the final seal when the ears have been folded and glued to the side walls.

A quick-setting thermoplastic or hot-melt adhesive is used in the preferred embodiment of the invention. The adhesive has the ability to sufficiently seal together the closure flaps before the natural spring-back of the cartonboard causes separation at the adhered surfaces. Various quick-setting adhesives will be familiar to those skilled in the art. However, the preferred adhesive for use with this carton is solid at room temperatures but sufiiciently fluid at temperatures of about 250 to 400 F. to permit rapid application to the surfaces by conventional means. Thermoplastic or hot-melt adhesives cool rapidly and solidify upon application thereby hardening in less than 0.50 second. Since the hot-melt adhesive solidifies on cooling, if desired, artificial cooling may be practiced. The adhesive is applied by conventional means to areas 42 and 43 of closure flaps 34 and 36, respectively. The size of the adhesively coated area will vary according to various carton sizes but generally the adhesive is applied to substantially the area of overlap when the closure flaps are infolded. Where the overlap area is greater than the amount of adhesive surface requirements for effective sealing, a strip or adhesive pattern may be desirable. In an alternative embodiment, it may also be desirable to use a strip of hot-melt adhesive with conventional slow-setting glue to complete the fastening.

In FIGURES 4, 5 and 6 the partially sealed end has been shown out of proportion to illustrate the void 54 (see FIG. 5) at the corners of the carton and the sealing function of the bafile flaps 46 and 50 after the closure flaps 28 and 36 have been folded and adhesively secured. The void 54 can be the principal point of product leakage at this stage of the carton structure. The leakage would occur at the juncture of the baffie flap extending from the carton side wall and the adhered closure flaps. As previously described, the problem of product leakage results because the carton is filled and moved on the packing line with the bottom end partially sealed to a point as heretofore described.

In most paperboard materials used for commercial cartons, there is a natural tendency for scored and folded flaps to spring back to the original flap condition of the carton blank. Because of this inherent property of paperboard, the closure flaps 28 and 36 (FIG. 5), even though folded and adhesively secured, do not lie in a flat plane but tend to bow-out thus exposing the void 54 when the end of the carton is partially sealed. This bow-out in a cross-section resembles a catenary shape. As shown in FIG. 6, the arcuate and straight line portions of the leading edge of the bafile flap 46 fit in substantially tight line contact with the inside surfaces of the closure flaps 28 and 36 at the partially sealed end of the carton.

Looking again at FIGURE 6, it will be seen that the configuration of the outer edge of the bafile fiap 46 (bent inwardly) fits tightly against the infolded closure flaps 28 and 36 to seal the void 54 thereby preventing material leakage at the corner of the carton. In other words, the outer edge of the baffle flap is configured to substantially conform to the inside contour of the closure flaps as they tend to bow-out. In this position the balfie flap acts as a short, stiff mechanical baffle which serves as a dependable sift-proofin-g device between the leading edge of the baffle and the inside surfaces of the closure flaps. Having been partially sealed in this manner, it is now possible to fill the carton with a powdery product without leakage even though the final sealing of the carton end has not been completed.

The method of forming and sealing the ends of the carton will now be discussed. In the practice of the method it is possible to use a mandrel M together with the roller R and an electromagnet E as shown in FIGURE 8. The mandrel M comprises a magnetizable structure in the form of a rod, bar or the like, cantilevered from a fixed support. The mandrel tapers smoothly from the larger end at the fixed support to a thin flexible springlike blade at the distal end. Iron, steel or any material having magnetic propensities under the influence of an electrical field are usable in the illustrated embodiment. Preferably the mandrel M when used on a conventional high speed packing line is located between the carton blank storage magazine and the product filling machine. Alternative locations are equally adaptable so long as one carton end is partially sealed before the carton is filled with product.

Collapsed cartons are magazine stored, opened and squared by conventional equipment and methods well known in the art. The squared-up carton is moved over the fixed end of the mandrel M and by use of known flap folding instrumentalities the baffle flaps 46 and 50 (FIG. 8) are infolded against the mandrel. As the carton advances, one closure flap 28 is folded over the mandrel, i.e., with the mandrel interposed between the baffle flaps and the closure flap 28. Next, the hot-melt adhesive is applied to the adhesive area 43 of the closure flap 36 by conventional means (not shown) and then the closure flap 36 folded over against the closure flap 28. The closure flaps 28 and 36 are superposed at the adhesive area 43. As the carton continues its advance, the overlapped closure flaps pass overIthe stationary roller R and electromagnet E. When the electnomagnet E is energized, a substantial nip pressure is exerted to hold the overlapped adhered surfaces of the flaps 28 and- 36 tightly together as the carton closure flaps 28 and 36 pass between the roller R and the mandrel M. The baflle flaps 46 and 50, which have been previously infolded, bear against the upper side of the mandrel M due to the natural spring of the paperboard carton material. In other words, as the carton is moved along the mandrel M toward its free end, the overlapped closure fiaps are pinched or squeezed between the roller R and the mandrel M.

The mandrel M is thin and flexible at the free end and would be deflected away from the roller R as the closure flaps are moved between them. If this happened, the necessary pressure for sealing the quick-set adhesive at the overlap of the closure flaps would be insufiicient for effective sealing. However, the electromagnet E located near the roller creates a magnetic field which draws the thin flexible end of the mandrel toward the roller thereby adding substantially to the compressive force applied to the adhesive area of the closure flaps. In this manner sufficient compressive force can be applied at the overlap area to firmly secure the hot-melt adhesive to the closure flaps for an effective partial seal of the carton end. Once the carton has moved beyond the roller, the closure flaps spring outward into the bowout shape and the battle flaps spring into line contact against the inner surfaces of the closure flaps thereby providing the previously described mechanical seal. All of these steps are performed continuously as the carton moves along the line at high linear speed.

FIGURE 9 shows, in expanded detail, the mandrel M in its position between the baffle flap 46 and the closure flaps 28 and 36 just before the carton moves beyond the mandrel M. This is the position wherein closure flaps 28 and 36 are under the maximum nip pressure exerted by mandrel M and roller R because of the force created by the field of the electromagnet E.

When the carton (one end only partially sealed) is filled with detergent granules or any similar product, a certain amount of jostling, bouncing or vibrating of the carton is desirable to settle the product. Rough handling of the partially filled carton in this fashion increases the tendency to bow-out and thus increase the size of the void at .the bottom of the carton which has, as yet, not been finally sealed. It has been found that the mechanical sealing effect of the baflle flaps is suflicient to prevent leakage and sitting past the partially sealed end during this filling process.

After the carton is filled, the open end is sealed in a similar manner as the bottom. This is illustrated in FIG- URES l and 11 wherein the bafiie flaps 44 and 48 pass under the mandrel M. The roller R together with the electromagnet E is positioned above the carton. This means, of course, that the bafile flaps 44 and 48 in the illustrated embodiment are first folded down so that they bear up against the mandrel M. Thereafter, the closure flap 26 is folded over the top of the mandrel M'. The hot-melt adhesive is applied by conventional means (not shown) at the area 42 of the closure flap 34 and the flap 34 is folded into super-posed relation with closure flap 2-6. The overlapped closure flaps 26 and 34 are then passed under the roller R and electromagnet E thereby squeezing the superposed portions of the closure flaps tightly against the mandrel M. The squeezing force is exerted for from FIGURE 11 that additional nip pressure on the closure flaps 26 and 34 can be achieved by the use of the mandrel M, roller R and electromagnet E in the identical manner as previously discussed for partially sealing the lower end of the carton prior to filling. In other words, the mandrel M and the roller R are drawn together by the force created by the field of the electromagnet B so that the overlapped portion of closure flaps 26 and 34 are squeezed tightly together.

In; FIGURES 12 and 13, the ears 30-33 and 38-41 have been bent so that they lie in the plane of the side walls. A conventional roll-type applicator W is used to apply an adhesive to the ears as the carton is moved past;Generally, a slow setting glue is used. Next, the ears- 30-33 and 38-41 are folded and adhered against the side walls 22 and 24. The carton is then passed between conventional compression belts (not shown) arranged to hold the ears firmly against the sidewalls until the glue hardens thus completing the carton.

A fragmentary view of one completed end of the carton is shown in FIGURE 7. The cars 30 and 39 have been scaled to the side wall 24 as shown. All of the other ears would be similarly sealed to their respective side walls.

While particular embodiments of the invention have been illustrated and described, it will be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention and it is intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.

What is claimed as new is:

1. A method of sealing a continuously moving, nonheat scalable carton wherein said carton has a pair of opposed baflle flaps and a pair of opposed closure flaps comprising the steps of infolding said baflie flaps to a generally coplanar position as the carton is advanced with its end adjacent a ferromagnetic, stationary mandrel, infolding one of the said closure flaps against said mandrel, applying a quick-setting, thermoplastic adhesive to at least one of the said closure flaps, infolding the remaining closure flap to overlap said first folded closure flap, holding the overlapped closure flaps together to seal said closure flaps at the area coated with adhesive by advancing the overlapped flaps between said mandrel and a cooperating stationary roller, applying a magnetic field to said mandrel to pull said mandrel against said roller whereby the pressure on the adhesively coated surface of said overlapped closure flaps is increased, and thereafter advancing the carton and said adhesively secured flaps beyond the mandrel.

2. The method claimed in claim 1 wherein the said overlapped closure flaps pass between the mandrel and the roller in less than 0.50 second.

3. A method of sealing a continuously moving, nonheat sealable carton having a pair of opposed bafile flaps and a pair of opposed closure flaps at each end, each of said closure flaps having sealing ears extending from each end thereof comprising the steps of infolding said bafile flaps at one end of the carton to a generally coplanar position as the carton is advanced over a ferromagnetic, stationary mandrel, infolding one of the said closure flaps at said one end over the said mandrel applying a quick-setting, thermoplastic adhesive to at least one of the closure flaps, infolding the other said closure flap at said carton end to overlap said first-folded closure flap, holding the overlapped closure flaps at said one end to seal said closure flaps together at the adhesively coated area by advancing the overlapped closure flaps between the said mandrel and a stationary cooperating roller, applying a magnetic field to said mandrel to pull said mandrel against said roller to increase the pressure on the overlapped surfaces of said closure flaps, filling the carton with product, infolding said bafile flaps at the other end of the carton to a generally coplanar position as the carton is moved under a second ferromagnetic, stationary mandrel, infolding one of said closure flaps at said other end of said carton over said second mandrel, applying an adhesive to at least one of the closure flaps at said other end of said carton, infolding the remaining closure flap to overlap said infolded closure flap, holding the overlapped closure flaps together thereby sealing the said closure flaps at the adhesively coated area as the carton is moved along the second mandrel, advancing the overlapped closure fiaps between the said second mandrel and a second stationary cooperating roller, applying a magnetic field to said second mandrel to pull said mandrel against said second roller, and folding and adhesively securing the said sealing ears to the side Walls.

4. A method as claimed in claim 3 wherein each of the said overlapped closure flaps at said carton ends passes between its mandrel and its roller in less than 0.50 second.

References Cited UNITED STATES PATENTS 2,293,498 8/1942 First et al 5347 2,496,336 2/1950 Cupo 53-47 X 2,524,032 10/1950 Back 5347 2,982,334 5/1961 Cooper et al l0093 3,094,265 6/1963 Howland 229 -37 3,140,809 7/1964 Hickin et al. 229 37 3,055,152 9/1962 Williams 5329 3,085,374 4/1963 Powell 53 29 2,712,209 7/1955 Brabender 53374X 3,191,353 6/ 1965 Chidsey 53-374X FOREIGN PATENTS 346,152 6/ 1960 Switzerland.

TRAVIS S. MCGEHEE, Primary Examiner.

FRANK E. BAILEY, N. ABRAMS, S. ABEND,

Assistant Examiners. 

1. A METHOD OF SEALING A CONTINUOUSLY MOVING, NONHEAT SEALABLE CARTON WHEREIN SAID CARTON HAS A PAIR OF OPPOSED BAFFLE FLAPS AND A PAIR OF OPPOSED CLOSURE FLAPS COMPRISING THE STEPS OF INFOLDING SAID BAFFLE FLAPS TO A GENERALLY COPLANAR POSITION AS THE CARTON IS ADVANCED WITH ITS END ADJACENT A FERROMAGNETIC, STATIONARY MANDREL, INFOLDING ONE OF THE SAID CLOSURE FLAPS AGAINST SAID MANDREL, APPLYING A QUICK-SETTING, THERMOPLASTIC ADHESIVE TO AT LEAST ONE OF THE SAID CLOSURE FLAPS, INFOLDING THE REMAINING CLOSURE FLAP TO OVERLAP SAID FIRST FOLDED CLOSURE FLAP, HOLDING THE OVERLAPPED CLOSURE FLAPS TOGETHER TO SEAL SAID CLOSURE FLAPS AT THE AREA COATED WITH ADHESIVE BY ADVANCING THE OVERLAPPED FLAPS BETWEEN SAID MANDREL AND A COOPERATING STATIONARY ROLLER, APPLYING A MAGNETIC FIELD TO SAID MANDREL TO PULL SAID MANDREL AGAINST SAID ROLLER WHEREBY THE PRESSURE ON THE ADHESIVELY COATED SURFACE OF SAID OVERLAPPED CLOSURE FLAPS IS INCREASED, AND THEREAFTER ADVANCING THE CARTON AND SAID ADHESIVELY SECURED FLAPS BEYOND THE MANDREL. 